Pretty sure the R70 pump's FPR is a different part number from the standard R65 one. This combined with the fact your's sounds like it isn't tight could well be the issue here.
The fact that it isn't tightly fitted into the pump doesn't bode well though, as Aaron said, air will get in if it's not sealed properly.
The fact that it isn't tightly fitted into the pump doesn't bode well though, as Aaron said, air will get in if it's not sealed properly.